Gulf of Tonkin Resolution, also called Tonkin Gulf Resolution, resolution put before the U.S. Congress by President Lyndon Johnson on Aug. 5, 1964, assertedly in reaction to two allegedly unprovoked attacks by North Vietnamese torpedo boats on the destroyers Maddox and C. Turner Joy of the U.S. Seventh Fleet in the Gulf of Tonkin on August 2 and August 4, respectively. Its stated purpose was to approve and support the determination of the president, as commander in chief, in taking all necessary measures to repel any armed attack against the forces of the United States and to prevent further aggression. It also declared that the maintenance of international peace and security in Southeast Asia was vital to American interests and to world peace.

Both houses of Congress passed the resolution on August 7, the House of Representatives by 414 votes to nil, and the Senate by a vote of 88 to 2. The resolution served as the principal constitutional authorization for the subsequent vast escalation of the United States’ military involvement in the Vietnam War. Several years later, as the American public became increasingly disillusioned with the Vietnam War, many congressmen came to see the resolution as giving the president a blanket power to wage war, and the resolution was repealed in 1970.

In 1995 Vo Nguyen Giap, who had been North Vietnam’s military commander during the Vietnam War, acknowledged the August 2 attack on the Maddox but denied that the Vietnamese had launched another attack on August 4, as the Johnson administration had claimed at the time.

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